Just to chime in from a driver's point of view: I've gotta agree that the cars bother/worry me more than escorts, in multiple ways.
1) As much as the back hills suck what with the potholes, spazzy streetlights, and other orgs right next to each other, there is a very narrow 'sweet spot' where the road is less crappy, and in a fairly straight run. At rolls its clear no problem--at push practice (as mentioned before) its essentially the line behind where the cars are parked.
2) When (not if--this is Pittsburgh) my windscreen does fog up, I just rely on the flashlight to steer towards. Generally thats fine, but the problem there is that the people actually holding the flashlight rarely put it exactly at the far end of the smoother stretch, and occasionally they actually end up holding it close enough to the parked car side that I'd be going unnervingly close to cars or trucks just sitting there. I'm not trying to say that this is any fault of the flashlight people, it's just that, particularly with trucks on the back hills, it could easily turn into a problem.
2b) Another important distinction between parked cars on the back hills and escorts rollin through: Escorts are annoying, and often semi-blinding, but at least I always know where they are. Dark cars parked (therefore with no headlights) are significantly harder to see, fogged or not.
3) I can just shut my eyes when I'm sitting on the sidewalk and cars or escorts drive by with their brights on, but (depending on how grumpy I already am from push practice etc so far that night) I sometimes worry that they don't actually know how close they drive to buggies. Being close to the ground is fun for driving, but just because they can see the pushbar doesn't ensure they see the nose of the buggy where my head is.
The other thing I wanted to mention is that, because I'm aware of all of these things/problems/concerns and I've seen Basketcase in the Froom, if I do get shoved at a weird angle and I have to correct, I always go away from where cars are. It usually puts me on the least fun part of the road, but personally I'd rather that than hit or get wedged under a car.
Short of getting the back hills miraculously repaved, I don't really know a solution. Moving the Escort stop might be helpful, but since we usually need to take a break between chunks of push practice anyway, I'm less vehement about that. If there's any possibility of making the back hills small-car-only parking, that might help some, but I've got no idea where to even start with that--particularly since quite a few orgs use trucks to drive their buggies from their rooms to the hills each night.
Thats my 3 cents. Once again, sorry for the overly long post.